Electrical connecting device and electron gun equipped therewith



Sept. 6, 1966 P. THOME ETAL 3,271,611

ELECTRICAL CONNECTING DEVICE AND ELECTRON GUN EQUIPPED THEREWITH Filed July 15, 1965 2 Sheets-Sheet l l NVEN TOR 5 THO/WE HL BERT Peal/LE PAUL Fave ROUD/ER m ATTORNEYS Sept. 6, 1966 P. THOME ETAL 3,271,611

ELECTRICAL CONNECTING DEVICE AND ELECTRON GUN EQUIPPED THEREWITH Filed July 15, 1963 2 Sheets-Sheet 2 Fig.3

INVENTORS PA 01. THO/v15 14L BERT PfCULE Pav Romy/ER BY (7M ATTORNEYS United States Patent 3,271,611 ELECTRICAL CONNECTING DEVICE AND ELEC- TRON GUN EQUIPPED THEREWITH Paul Thome, Saint-Cloud, Albert Recule, Iguy, and Rene Roudier, Sucy-en-Brie, France, assignors to Commissariat a lEuergie Atomique, Paris, France Filed July 15, 1963, Ser. No. 294,976 Claims priority, applicatiori France, July 18, 1962, 9 3

4 Claims. (a. 313-149 It is known that achieving electrical connections between fixed terminals and movable terminals is attended by a number of difiiculties, in particular when these conmotions are to be made under vacuum. This last named case applies notably to' electron guns used for welding, evaporation, fusion and like operations, since these guns must be moved under vacuum during the operation (fusion of predetermined zones, line welding, etc.).

These movements are attended by many technical difficulties inherent in the behaviour of electrical contacts sliding or rubbing under vacuum. When electron guns equipped with particularly elaborate and carefully made optical systems are used variations in the filament heatingacting as a cathode or used for heating by bombardment a massive cathode having a predetermined geometryinvolve a certain irregularity in the high-voltage current. whenever it is desired to derive the maximum advantage from the gun performance and from the operating constant of these electron guns, for instance with a view to preserve the regularity of deep-penetration weld seams, a feature unattainable unless a high degree of stability of the electrical characteristics is maintained.

It is the essential object of the present invention to avoid the various drawbacks set forth hereinabove by pro viding a device for making an electrical connection between a terminal movable in a plane and a fixed terminal adjacent to said plane, which comprises a strip of resilient metal having a cross-section in the form of a circular arc with an angle ranging from to 90 when the strip is unstressed and decreasing substantially to 0 when a stress is applied thereto to curve the center line of said strip, the end portions of said strip, which are secured on the terminals, extending in directions substantially parallel to the plane of movement of said movable terminal and such that said center line may assume, irrespective of the position of said movable terminal, the shape of a circular arc of an amplitude ranging from 120 to 210", this are being disposed between two rectilinear portions of variable length, the center line of the strip actually assuming this shape.

This invention is also concerned with an electron gun comprising a plurality of electrical connecting devices of the type broadly set forth hereinabove, wherein each metal strip has one end secured on a fixed terminal of an electrical junction or like member, and its other end secured on a terminal rigid with the movable body of the electron gun, each strip being furthermore contained in a substantially horizontal plane.

The present invention also comprises the features described hereinafter and also their various possible combinations.

In order to afford a clearer understanding of this invention and of the manner in which the same may be carried out in practice, reference will now be made to the accom- Now these irregularities should be avoided- 3,271,611 Patented Sept. 6, 1966 panying drawings illustrating diagrammatically by way of example a typical electron gun construction incorporating connecting devices according to this invention. In the drawings:

FIGURE 1 is a fragmentary front elevational and sectional View showing the electron gun of this invention;

FIGURE 2 is a diagrammatic plan view from above showing the electron gun of FIG. 1 and more particularly the general configuration of the current-conveying strip, and

FIGURE 3 is a cross section taken upon the line II of FIG. 2, showing the metal strip on a larger scale.

The electrical connecting device of this invention comprises essentially a metal strip extending between a fixed terminal and a movable terminal for conveying current, and which is so disposed that in a plane at right angles to the cross section of said strip the latter has a rigidity sulficient to prevent its flexion or sagging, and that in the plane of said cross sectionthe same strip has a flexibility sufiicient to permit the movements of said movable terminal in relation to its companion fixed terminal.

The invention will be set forth more in detail with reference to the electron gun illustrated in FIGS. 1 to 3 of the attached drawings, this gun constituting a typical embodiment of the connecting device of this invention.

The electron gun assembly illustrated in FIGS. l-3 includes a vacuum-tight chamber 1 having an opening therein over which is secured an inverted cup member. A flanged cap 2 is received over the cup member and is secured in position, and the bottom walls of the inverted cup member and the flanged cap 2 are provided with aligned bores within which are mounted vacu umsealed high-voltage inlet passage means 3. Each passage means 3 comprises a flanged insulating socket 4 having an electrical junction 5 mounted therein, the flange on each socket 4 being clamped between the end walls of the inverted cup member and the flanged cap 2, and suitable gasket means 6 being provided for sealing purposes. A high-voltage outlet member 7 is mounted in each sleeve 4 on the atmosphere side thereof and with its inner end engaging the electrical junction 5, and each passage means 3 has an inner extension extending into the vacuum-tight chamber 1 in the form of a terminal 8, two terminals 8 being shown in FIG. 1. Mounted inside the vacuum-tight chamber 1 is the electron gun proper comprising a body 9, high-voltage input terminals 10, and insulators 11, this assembly being mounted on a carriage 12 movable on rails 13. The carriage is driven through simple mechanical means (not shown). Finally, the electric insulators 11 are protected by screen means 14 from metallization effects produced by the electron gun.

In the embodiment illustrated in FIG. 1 the electrical connection between the fixed terminals 8 and the movable terminals 10 of the electron gun is efiected by means of resilient metal strips 15 having their ends secured to said terminals 8 and 10, respectively. In FIG. 1, only the initial portions 15a and the end portions 15b of two strips interconnecting a pair of fixed terminals 8 and a pair of movable terminals 10 are shown. FIG. 2, which is a diagrammatic plan view from above of the electron gun shown in FIG. 1 illustrates the specific configuration of the two metal strips conveying current between the two fixed terminals 8 and the two movable terminals 10. These resilient metal strips are roughly of hairpin configuration and comprise two rectilinear parallel portions 15 and 15;, joined by a semi-circular portion 15 of a curvature permitting notably the longitudinal and transverse displacement of the movable terminals in relation to the fixed terminals 8, without interfering with the electrical connection.

The cross section of the relaxed rectilinear portions and 15 (see FIG. 3) is bent or cambered to a circular arc configuration having an angular amplitude ranging from 10 to 90 and preferably from 40 to 45, thus increasing the rigidity and preventing any twisting or warping of the strip. Thus, the resilient metal strip remains substantially coplanar with the two terminals interconnected thereby, without being fastened otherwise than at its ends.

In the elbow portion 15 the cross section of the strip is flattened and the camber suppressed by the stress applied to the strip for curving same. The radius of the bent portion 15 should be suflicient to reduce to zero or substantially to zero the resistance of the cambered strip to a bending movement, without however exceeding a certain limit value since this resistance reappears when the curvature becomes relatively important; therefore, its angular amplitude or sector angle ranges from 120 to 210.

The radius of curvature 15 is kept as close as possible to the optimum value throughout the range of movements contemplated for the movable terminal, this feature being permitted by the considerable rigidity of the assembly.

On the other hand, the resilient strips 15 offer a certain stifiness in a plane at right angles to their cross section, thus providing an appreciable flexibility in the plane of their cross section, so that by simply fastening the two ends of each strip the latter will remain in this plane irrespective of the relative position of these ends.

When the carriage 12 rolls along the rails 13 the electron gun 9 and the movable terminals 10 move transversely and cause the straight sections 15 15 to move toward or away from each other, This movement changes the angular amplitude of the circular are 15 without modifying its radius, so that the camber remains unchanged.

In certain cases this transverse movement may be given a greater amplitude by mounting the strip on the terminals with a slight inclination in relation to the plane of movement of the movable terminal; thus, the strip can be slightly inclined in relation to the initial plane of the two terminals.

Under these conditions, the gun can be moved transversely in this plane and the rectilinear section of the strip secured on the movable terminal may cross the section secured on the fixed terminal.

The electrical connecting device of this invention likewise aifords longitudinal movements of the gun 9 and terminals 10, and during these displacements the lengths of the rectilinear sections 15 and 15 are caused to vary without altering the radius of the half-circle 15 As this movement takes place the resilient strip cross-section is altered, the camber disappearing in the stressed curved portion and reappearing automatically in the relaxed rectilinear sections.

By way of example, in an electron gun constructed according to the teachings of this invenion four identical metal strips each having the following characteristics have been used as connecting elements between the fixed and movable terminals:

Length 400 millimeters.

Width 15 millimeters.

Thickness 0.1 millimeters.

Camber millimeters radius.

Curvature Radius ranging from 18 to 20 mm.

The steel stock used was spring steel.

A current of up to 2 or 3 amperes can be circulated in this strip.

Although the present invention has been described in conjunction with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

What we claim is:

1. A device for eifecting an electrical connection between a terminal movable transversely and longitudinally in a first plane and a fixed terminal disposed adjacent to said first plane, comprising: a generally U-shaped resili-. ent metal strip having a cross-section approximately of circular arc configuration with an angular amplitude of 10 to when said strip is relaxed and no bending stress is applied thereto, said strip including a pair of rectilinear sections extending generally longitudinally of said first plane and connected by a bent, generally semicircular elbow section defining a circular arc of an ampli tude ranging from to 210, all of said sections lying generally in .a second plane extending generally parallel to said first plane, the outer ends of said rectilinear sections being secured respectively to said movable terminal and said fixed terminal, and the amplitude of said resilient strip cross-section being substantially zero at a region within said elbow section so that said strip is substantially flat in said region, said region of said strip remaining substantially flat while said nectilinear sections of said strip are moved toward and away from each other during transverse movement of said movable terminal and while the lengths of said rectilinear sections remain generally constant, and said substantially fiat region of said strip in said elbow section moving along the length of said resilient strip as the lengths of said rectilinear sections are varied with respect to each other during longitudinal movement of said movable terminal while the portions of said resilient strip on opposite sides of said region retain their curved crosssections, whereby the portion of said resilient strip extending between the secured outer ends thereof is self-supporting.

2. A device as recited in claim 1, wherein said movable terminal is disposed beneath'said fixed terminal, and wherein the outer ends of said resilient strip are secured to their respective terminals so that the centerlines of said rectilinear sections are slightly and oppositely inclined with respect to said first plane, thereby permitting movement of said movable terminal until it underlies said fixed terminal.

3. A device as recited in claim 1, wherein said strip is made of steel stock.

4. An electron gun assembly, including: a plurality of fixed electrical terminals; an electron gun body mounted below said fixed terminals for movement transversely and longitudinally in a first plane; a plurality of terminals on said gun body and movable therewith in said first plane, there being a movable terminal corresponding to each of said fixed terminals; and a device for effecting an electrical connection between each fixed'terminal and its corresponding movable terminal, each of said devices comprising: a generally U-shaped resilient metal strip having a cross-section approximately of circular arc configuration with an angular amplitude of 10 to 90 when said strip is relaxed and no bending stress is applied thereto, said strip including a pair of rectilinear sections extending generally longitudinally of said first plane and connected by a bent, generally semi-circular elbow section defining a circular arc of an amplitude ranging from-120 to 210, all of said sections lying generally in a second plane extending generally parallel to said first plane, the outer ends of said rectilinear sect-ions being secured respectively to said movable terminal and said fixed terminal, and the amplitude of said resilient str-ip cross-section being substantially zero at a region within said elbow section so that said strip is substantially fiat in said region, said 5 region of said strip remaining substantially flat while said rectilinear sections of said strip are moved toward and away from each other during transverse movement of said movable terminal and while the lengths of said rectilinear sections remain generally constant, and said substantially 5 fiat region of said strip in said elbow section moving along the length of said resilient strip as the lengths of said rectilinear sections are varied with respect to each other during longitudinal movement of said movable terminal while the portions of said resilient strip on opposite sides of said region retain their curved cross-sections, whereby the portion of said resilient strip extending between the secured outer ends thereof is self-supporting.

6 References Cited by the Examiner UNITED STATES PATENTS 2,361,202 10/ 1944 Hodgkins. 2,805,297 9/ 1957 Campbell. 2,959,634 11/1960 Lyon 174-69 JOHN W. HUCKERT, Primary Examiner.

10 DAVID J. GALVIN, Examiner.

D. E. PITCHENIK, D. O. KRAFT, Assistant Examiners. 

1. A DEVICE FOR EFFECTING AN ELECTRICAL CONNECTION BETWEEN A TERMINAL MOVABLE TRANSVERSELY AND LONGITUDINALLY IN A FIRST PLANE AND A FIXED TERMINAL DISPOSED ADJACENT TO SAID FIRST PLANE, COMPRISING: A GENERALLY U-SHAPED RESILIENT METAL STRIP HAVING A CROSS-SECTION APPROXIMATELY OF CIRCULAR ARC CONFIGURATION WITH AN ANGULAR AMPLITUDE OF 10* TO 90* WHEN SAID STRIP IS RELAXED AND NO BENDING STRESS IS APPLIED THERETO, SAID STRIP INCLUDING A PAIR OF RECTILINEAR SECTIONS EXTENDING GENERALLY LONGITUDINALLY OF SAID FIRST PLANE AND CONNECTED BY A BENT, GENERALLY SEMICIRCULAR ELBOW SECTION DEFINING A CIRCULAR ARC OF AN AMPLITUDE RANGING FROM 120* TO 210*, ALL OF SAID SECTIONS LYING GENERALLY IN A SECOND PLANE EXTENDING GENERALLY PARALLEL TO SAID FIRST PLANE, THE OUTER ENDS OF SAID RECTILINEAR SECTIONS BEING SECURED RESPECTIVELY TO SAID MOVABLE TERMINAL AND SAID FIXED TERMINAL, AND THE AMPLITUDE OF SAID RESILIENT STRIP CROSS-SECTION BEING SUBSTANTIALLY ZERO AT A REGION WITHIN SAID ELBOW SECTION SO THAT SAID STRIP IS SUBSTANTIALLY FLAT IN SAID REGION, SAID REGION OF SAID STRIP REMAINING SUBSTANTIALLY FLAT WHILE SAID RECTILINEAR SECTIONS OF SAID STRIP ARE MOVED TOWARD AND AWAY FROM EACH OTHER DURING TRANSVERSE MOVEMENT OF SAID MOVABLE TERMINAL AND WHILE THE LENGTHS OF SAID RECTILINEAR SECTIONS REMAIN GENERALLY CONSTANT, AND SAID SUBSTANTIALLY FLAT REGION OF SAID STRIP IN SAID ELBOW SECTION MOVING ALONG THE LENGTH OF SAID RESILIENT STRIP AS THE LENGTHS OF SID RECTILINEAR SECTIONS ARE VARIED WITH THE RESPECT TO EACH OTHER DURING LONGITUDINAL MOVEMENT OF SAID MOVABLE TERMINAL WHILE THE PORTIONS OF SAID RESILIENT STRIP ON OPPOSITE SIDES OF SAID REGION RETAIN THEIR CURVED CROSS-SECTIONS, WHEREBY THE PORTION OF SAID RESILIENT STRIP EXTENDING BETWEEN THE SECURED OUTER ENDS THEREOF IS SELF-SUPPORTING. 